This invention relates to apparatus for producing business forms which have multiple web plies and, more particularly, to apparatus which is characterized by flexibility and interchangeability to facilitate production of limited quantities of customized forms.
The cost to produce a "short run" of business forms is significantly higher than that of a longer run--because the set-up time is about the same. Therefore, users of forms have had to compromise--either taking a standardized form which does not meet the users criteria or compromise with quality in the customized forms. One compromise, for example, might be the acceptance of the same color on each web despite the fact that web to web differences have been well known to reduce end-processing errors and usage cost.
In recent years there has been a significant change in the complexity of business forms because the increasing variety of end use applications such as data retrieval and print-out. Thus, the whole trend is to go to more complex forms but the user of limited quantities of forms really was going opposite to the trend because of the inability of the art to produce an economical short run machine. More particularly, the art could not supply a machine with the requisite flexibility for quick change-over to accommodate special requirements, i.e., special characteristics. By the term "characteristics", we refer to characteristics of business forms. Historically, these can be processing characteristics such as gluing, line hole punching, file hole punching, crash numbering, slitting, crimp locking, cross perforation and folding for continuous forms (or cut-off and stacking for snap-out forms; or printing characteristics which include such factors as color, repeat length, image or pattern, distribution (between front and back) and combinations thereof.
Single web processing including duplicate colors and operations for each web plus a secondary and subsequent collating operation of the plurality of webs into multiple copy forms is current commercial practice for short run orders, but higher productivity could be achieved in processing these orders in a one-step operation on a multi-web press if the set-up time could be reduced. A major disadvantage of single web processing-collating includes the handling costs of processed rolls from the single web press to a collator with the attendant risk of damaging rolls that have substantial value added at this process point. It is also noted that single web processing/collating includes a greater number of start-ups with attendant web threading problems which can cause waste, and the problems of length control and register of part to part is also more difficult, vis-a-vis, the multi-web processing method. Other disadvantages of single web processing involves the storage of rolls that have been single web processed before collating and during storage, changing moisture conditions, shrinkage, etc., of these finished rolls.
Simultaneous processing of multiple webs, including functions such as line and file hole punching, perforating, and printing variations, etc., can be performed at higher average speeds than collating machines since simultaneous processing avoids web-to-web mis-register and attendant problems. However, multi-web processing has heretofore been limited to less complicated forms and longer production runs since existing multiple web business forms machines do not permit easy changes or additions of processing steps for individual webs, this flexibility being required for "customized" forms which may include, but are not limited to a selection of: dry offset printing, wet offset printing, flexographic printing, gravure printing, carbon spot printing, numbering, corner cutting, cross perforation, linear perforation, gluing, file hole punching, die cutting, etc.
The inventive apparatus is arranged to permit any combination of these processing steps and defines structures which permit rapid web handling and change-over of unit modules in any combination, thereby allowing greater processing flexibility on shorter production runs when producing forms according to multi-web processing methods.
In one preferred embodiment of the invention, the apparatus includes a plurality of towers arranged in horizontally spaced apart relation in the path of travel of a plurality of webs, viz., one tower for each web. Each tower has a plurality of vertically related modules arranged for vertical web travel therepast and it is these modules which may be changed over rapidly to achieve the heretofore unobtainable flexibility of operation, particularly for short production runs.
Notwithstanding the pressure on the art to develop a versatile apparatus for limited, custom forms, it is surprising that the art workers did not appreciate the instant invention--particularly in view of the fact that interchangeable modules have been known and used for a considerable period as have towers with a plurality of units therein. However, no one had seen fit to combine the two concepts.
The invention also includes a novel characteristic imparting module which facilitates change-over both in whole or in part so as to achieve a significant number of different characteristics in the webs with minimal change-over time. According to the invention, the printing module includes a blanket roll and a plate roll on which a printing plate is mounted. The blanket roll is pivotably mounted relative to the plate roll so that the blanket roll can be pivoted away from the plate roll to provide sufficient access to the plate roll to permit the printing plate to be quickly changed. If the repeat length is to be changed, the blanket roll assembly and the plate roll assembly can be quickly removed from the module and replaced with different size blanket and plate roll assemblies. The ink fountain is also removable so that the ink color can be changed merely by replacing the fountain. Other structures and functions of the invention which optimize multi-web processing in combination with individual single web processing for limited and special forms production can be appreciated from a consideration of the ensuing specification, it being understood that downstream multi-web processing applies to continuous forms when using a folder, or alternately applies to unit sets of business forms when using a cutoff mechanism and stacking delivery system.